I guess their born looking like adults but their mind still has to develop

So there are going to have stages/steps before becoming an adult

It’s quite possibly that they simply behave like children when they first appeared. So I think that when they mention ‘kids’ it’s kind of a code or metaphor for in their early years.

I'm going by what Lucifer says because I know he can't lie 😆

Just because Lucifer has the ability to tell the truth doesn't mean his mother can 😂